1. Field of the Invention
The present invention relates generally to the field of medical waste disposal devices. More specifically, it relates to an apparatus for destroying hypodermic needles so that they cannot be inappropriately reused and cannot transmit disease by pricking a waste handler. The apparatus includes a grinder and a needle guide structure for directing the needle into the grinder. The grinder includes an electric motor having a motor drive shaft and a grinding wheel mounted on the drive shaft. The grinder is enclosed within a cylindrical housing having a first chamber containing the motor and a second chamber containing the wheel, the chambers being separated from each other by a partition member. The drive shaft extends through a port in the, partition member. The second chamber includes an access wall opposite the partition wall, and a needle receptacle structure in the access wall in the form of an outer recess fitted with a photocell detection assembly. This detection assembly senses the insertion of a needle into the outer recess and activates the motor to rotate the grinding wheel. An inner recess receives and braces the needle hub and guides the needle shaft against the grinding wheel as the wheel grinds the needle shaft into fine grain particles. The particles fall into and collect in a tray in the lower end of the second chamber. The tray contains a replaceable liner sack and is removable for removal of a full liner sack and the particles contained therein and for replacement of the liner sack.
2. Description of the Prior Art
There have long been disintegration devices for battering and breaking medical waste items such as syringes. These devices almost invariably include a hopper for receiving the waste items, a disintegration chamber and a chute for delivering these items into the chamber. The disintegration chamber typically contains rotationally mounted and motor driven arrays of battering hammers or chains which spin and beat the waste items into bent pieces.
An example of such a device is that of Bryant, U.S. Pat. No. 3,322,355, issued on May 30, 1967. Bryant includes a tall housing with the waste hopper at the top, an angled waste carrying chute below the hopper for gradually delivering the waste into the disintegration chamber, a motorized axle extending through the chamber with a series of radially mounted hammer members extending therefrom, and a collection bin in the bottom of the housing. Dryden, et al., U.S. Pat. No. 3,926,379, issued on Dec. 16, 1975, teaches a hypodermic syringe disintegrator. Dryden is very similar to Bryant except that the hopper is largely eliminated and an oscillating pump circulates disinfectant liquid through the waste material path. The collection bin includes a disposable waste bag, from which accumulated disinfectant liquid is pumped back up into the inlet waste chute. Horton, et al., U.S. Pat. No. 4,205,794, issued on Jun. 3, 1980, reveals a hypodermic syringe destruction device. Horton is much like Dryden except that the hammer elements are replaced with functionally similar flexible chain members. The chain members swing radially on a shaft within the destruction chamber, and flex upon striking large objects to be comminuted. An arcuate screen is positioned adjacent the chain member distal ends to permit passage of comminuted articles. Koffasky et al., U.S. Pat. No. 4,809,915, issued on Mar. 7, 1989, teaches a waste disposal apparatus much like those mentioned above, except that the hammer members in the destruction chamber have sharpened edges to act as cutting blades. Chopped waste items are collected in a lined container below the chamber, and the container rides on a cart. Montalbono, U.S. Pat. No. 3,929,295, issued on Dec. 30, 1975, teaches an apparatus for destroying syringes and like articles. The waste articles are advanced between serrated stationary elements and serrated moving elements to bend and cut the waste articles. Maitlen, et al., U.S. Pat. No. 5,025,994, issued on June 25, 1991, discloses an apparatus for cutting up hypodermic syringes or needles. Maitlen includes a plurality of cylindrical rotors within a chamber, each rotor having radially extending teeth which interact with each other to cut the syringes and needles. The word "grinding" is used in Maitlen, but the action performed is more that of cutting and breaking. Chang, U.S. Pat. No. 5,064,124, issued on Nov. 12, 1991, teaches a medical waste disposal system. Chang mentions some sort of grinding assembly, but does not explain its structure.
Problems with these devices include their substantial bulk and expense. A more important problem is that, while a syringe needle may be bent or broken in one or two places, it still retains its ability to prick and penetrate the skin, and thereby to transmit deadly diseases to waste handlers. FIG. 1B of Montalbono shows the results of such waste processing, and the needle is shown to be simply bent, and still dangerous. And where waste is improperly or illegally dumped, the sharp needles may be spread around a neighborhood or a beach where children may step on them. These expensive, prior devices fail to effectively disarm what may be the most deadly element of medical waste.
It is thus an object of the present invention to provide a grinding apparatus which can receive all sizes and lengths of used hypodermic needles and quickly grind the needle shaft into a mass of very fine particles for safe disposal with no risk of accidental skin penetration or improper reuse to minimize the spread of contagious diseases.
It is another object of the present invention to provide such an apparatus which both conceals and holds the needle shaft steady during the grinding operation for ease and safety of handling.
It is still another object of the present invention to provide such an apparatus which is self-activating, so that when a needle is inserted into the apparatus, the grinding elements within the apparatus automatically activate, and then deactivate upon removal of the remaining plastic needle hub.
It is finally an object of the present invention to provide such an apparatus which delivers the ground particles into a sealed container having a liner for ready disposal, and to provide such an apparatus which is simple, compact, portable, reliable and inexpensive to manufacture.